The purpose of the proposed investigation is to astablish a model to study immunoprophylaxis and immunotherapy of lung cancer. Previous studies have indicated that BCG will induce a degree of protection against progressive tumor growth. We would like to extend these studies to include a lung tumor model. It is assumed that a greater understanding of the conditions necessary for immunological interruption of the oncogenic process will provide useful clues for treating lung cancer and lung metastasis in man. Our specific objectives are: (1) to determine the conditions necessary for successful induction of tuberculin hypersensitivity and lung granulomas in hamsters with viable and nonviable BCG preparations; (2) to study the effects of BCG treatment on the latent period and incidence of benzo(a)pyrene induced bronchogenic carcinoma in hamsters; (3) to study tumor biology of transplantable lung tumors in order to establish a model for immunotherapy of lung metastasis; (4) to develop in vitro assays for the purpose of studying immunity to lung tumors, and of studying BCG immunologic intervention; (5) to study the immunosuppressive effects of carcinogen and the role BCG might play in counteracting the immunosuppressive action of benzo(a)pyrene.